Yunnan Xuanwei Ham (宣威火腿/xuān wēi huó tuǐ)
Eben van Tonder
10 May 2020
Yunnan is one of China’s premium food regions known for exquisite tastes. One of the major cities in this picturesque region is Xuanwei, where one of the world famous Chinese hams are produced, the others being Jinhua Ham from Zhejiang province and Rugao Ham from Jiangsu province. Yunnan Xuanwei Ham is known for its fragrance, appearance, and out-of-the-world taste. Through the ages, there have been many references in literature to the health benefits associated with the hams. In order to produce these hams, there are at least two ingredients without which the hams can not be produced. The first ingredient is salt.
The Industrialisation of Ham
Early references to Xuanwei hams go back to 1766. “Old chronicles recorded the Qing emperor Yong Zheng five years (the year 1727) located XuanWei (a city of YunNan province, China), so it is called XuanWei ham. (China on the Way) In 1909, Zhuo Lin’s (Deng Xiaoping’s third wife) father Pu Zai Ting, a businessman, mass-produced it for the first time. He established Xuanhe Ham Industry Company Limited. His company sent food technicians to Shanghai, Guangzhou (formerly Canton), and Japan to learn advanced food processing technology.
One example of the excellence pursued in Guangzhou relates to the cultivation of rice. Rice breeding began in China in 1906. However, by 1919, systematic and well-targeted breeding using rigorous methodologies was started at Nanjing Higher Agricultural School and Guangzhou Agricultural Specialized School. Between 1919 and 1949, 100 different rice varieties were bred and released. (Mew, et al., 2003) For a riveting look at the trade in Guangzhou, see the work by Dr. Peter C. Perdue, Professor of History, Yale University, Canton Trade.
By all accounts, Pu Zaiting was successful in creating a world famous ham (at least by probably standardising and industrialising the process). In 1915 Xuanwei ham won a Gold Medal at Panama International Fair. The ham, which, in the Qing and Ming Dynasties, was a necessary gift for friends and guests and which, during the gourmet festival, became the main ingredient to create different delicious dishes achieved international acclaim. (chinadaily.com)
The Xuanhe Canned Ham Industry Company Limited was established on the back of canning equipment bought from the United States of America to produce canned ham. Most of what it produced were exported overseas. In 1923 Sun Yat-sen tasted the ham at the National Food Exhibition held in Guangzhou. Sun famously wrote of the ham, “yin he shi de” translating as “eat well for a sound mind!” By 1934, four companies were producing the canned ham. (Kristbergsson and Oliveira, 2016)
Xuanwei Ham expanded greatly under the People’s Republic of China, established in 1949. Supporting industries started to develop. A factory was created to supply the cans used by the Municipal Authority of Kunming City. (Kristbergsson and Oliveira, 2016)
Production of Xuanwei hams rose by 1999 to 13 000 tonnes, made by 38 large producers. In 2001 it got the status of a regional brand, protected by the People’s Republic of China. A Chinese standard, GB 18357-2003 was subsequently issued. By 2004 production rose to 20,750 tonnes with technology in manufacturing and packaging improving continuously. (Kristbergsson and Oliveira, 2016)
Apart from a rich and competitive environment, an entrepreneur, as the proverb goes, worth his salt, was needed to bring discipline to the production process and to establish this ham among the finest on earth. In achieving this status, three elements were required, namely salt, the right meat and a solid production technique to yield this culinary masterpiece on an industrial scale.
Yunnan – Centre of Culinary Excellence
The first requirement for competitiveness is an environment of excellence and innovation. The environment where this exquisite ham is produced testifies to culinary excellence. Like Prague, which produced the ham press, nitrite curing and the famous Prague hams, the Yunnan hams likewise hail from an area replete with food and cooking innovations. Yunnan is located on what was known as the Southern Silk Road and its culinary excellence is seen, among other things, in the equipment used in preparing their foods. Joseph Needham, et al. reports that in restaurants in the cities of Yunnan, a very special dish is found “in which chicken, ham, meat balls and the like have been cooked in water just condensed from steam. This is done by means of an apparatus called chhi kuo (or formerly yang li kuo) made especially at Chien-shui near Kochiu. It consists simply of a red earthenware pot with a domical cover, the bottom of the pot being pierced by a tapering chimney so formed as to leave on all sides an annular trough (figure 1490). The chhi kuo once placed on a saucepan of boiling water, steam enters from below and is condensed so as to fall upon and cook the viands of the trough, resulting thus after due process in something much better than either a soup or a stew in the ordinary sense. Since the chimney tapers to a small hole at its tip no natural volatile substances are lost from the food, hence the name of the object and the purpose of its existence. The chhi kuo must claim to be regarded as a distant descendant of the Babylonian rim-pot (for it has and needs no Hellenistic side-tube) with the ancient rim expanded to form a trough, compressing the ‘still’-body to a narrow chimney. But how the idea found its way through the ages, and from Mesopotamia to Yunnan, might admit of a wide conjecture.” (Needham, et al.,1980)
The second essential ingredient for a salt-cured ham is salt. Salt is something that China has been specialising in for thousands of years and which became the backbone of the creation of this legend.
Salt in China
Flad, et al. (2005) showed that salt production was taking place in China on an industrial scale as early as the first millennium BCE at Zhongba. “Zhongba is located in the Zhong Xian County, Chongqing Municipality, approximately 200 km down-river along the Yangzi from Chongqing City in central China. Researchers concluded that “the homogeneity of the ceramic assemblage” found at this site “suggests that salt production may already have been significant in this area throughout the second millennium B.C..” Significantly, “the Zhongba data represent the oldest confirmed example of pottery-based salt production yet found in China.” (Flad, et al.; 2005)
Salt-cured Chinese hams have been in production since the Tang Dynasty (618-907AD). First records appeared in the book Supplement to Chinese Materia Medica by Tang Dynasty doctor Chen Zangqi, who claimed ham from Jinhua was the best. Pork legs were commonly salted by soldiers in Jinhua to take on long journeys during wartime, and it was imperial scholar Zong Ze who introduced it to Song Dynasty Emperor Gaozong. Gaozong was so enamored with the ham’s intense flavour and red colour he named it huo tui, or ‘fire leg’. (SBS) An earlier record of ham than Jinhua-ham is Anfu ham from the Qin dynasty (221 to 206 BCE).
In the middle ages, Marco Polo is said to have encountered salt curing of hams in China on his presumed 13th-century trip. Impressed with the culture and customs he saw on his travels, he claims that he returned to Venice with Chinese porcelain, paper money, spices, and silks to introduce to his home country. He claims that it was from his time in Jinhua, a city in eastern Zheijiang province, where he found salt-cured ham. Whether one can accept these claims from Marco Polo is, however, a different question.
Salt Production In and Around Yunnan
When it comes to salt, only a very particular variety is called on to create this legend.
Around the Yunnan-Guizhou plateau are three salt producing areas which took advantage of the expansion of China towards the west in the early modern era. “Szechwan with a slow but steady advance; Yunnan with the speed and initiative characteristic of a developing mining area; Mongolia with a sudden, temporary eruption.” (Adshead, 1988) As fascinating as Szechwan and Mongolia are, we leave this for a future consideration and hone in on Yunnan.
Szechwan not only supplied its own requirements for salt, but also that of Kweichow, Yunnan (trade started in 1726) and western Hupei. Despite the fact that Yunnan imported salt from Szechwan and possibly from Kwangtung, this was mainly to supply its eastern regions of the escarpment. On the plateau it had salt resources of its own. By 1800, it is estimated that it produced 375 000 cwt (hundredweight).”These salines formed three groups: Pei-ching in the west near Tali the old indigenous capital; the Mo-hei-ching or Shihi-koa ching in the south near Szemao close to Laotian and Burmese borders; Hei-ching in the east near the provincial capital Kunming. (Adshead, 1988) It is this last group that captures our imagination due to the connection with the Yunnan hams.
Although known as ching or wells, many of the Yunnan salines, especially those in the Mo-hei-ching group, were in the nature of shafts or mines, though the low grade rock salt was generally turned into brine and evaporated over wood fires. The growth of the Yunnan salines in the Ch’ing period was the product of two forces. First, Chinese mining enterprise, often Chinese Muslim enterprise, which in the 18th century was turning Yunnan into China’s major source of base materials – copper, tin and zinc. Second, the extension of direct Chinese rule into the area, the so-called kai-t’u kuei-liu, initiated particularly by the Machu governor-general O-er-t’ai between 1725 and 1732. (Adshead, 1988)
The distant past of Heijin comes to us, courtesy of Yunnan Adventure Travel, who writes that “the unearthed relics of stones, potteries, and bronze wares have proved that as early as 3,200 years ago, ancestors of some minority groups already worked and multiplied on this land. It’s recorded in the “Annals of Heijin” that, a local farmer lost his cattle when grazing on the mountain, he finally found his black cattle near a well; but to his surprise, when it lipped the soil around the well, salt appeared; thus in order to memorize the black well, the place was nicknamed as “Heiniu Yanjin” which means the black cattle and the salt well. It’s shortly referred to as Heijin afterwards.” (www.yunnanadventure.com) Some accounts of the story have it that it was a Yi girl who was looking for her missing oxen when she came upon them licking salt from the black well.
Who better to take us on a tour of the old town than a seasoned traveller! We meet such a wanderer in the old city of Heijin in the person of Christy Huang. She takes us on an epic adventure, discovering the old salt kingdom of Hei-ching. She posted it on Monday, November 30th, 2015 and she called her post “
Christy writes that “the quite fameless Old Town of Heijing (黑井古镇) – today one of the nicest in Yunnan – used to be famous for the high-quality salt which was produced there since hundreds of years. The once most important town of Yunnan is hidden at the banks of Longchuan River in Lufeng County of Chuxiong Prefecture of Yunnan.
Salt production in bigger scale began in the Tang Dynasty (618-907) and peaked during the Ming (1368–1644) and Qing (1644–1912) Dynasties. Besides the overall beautiful picture of Hejing and its surroundings, there are a couple of scenic spots worth mentioning:
- Courtyard of Family Wu,
- Ancient Salt Workshop,
- Dalong Shrine, as well as,
- Heiniu Salt Well.
The Courtyard of Family Wu used to be the residence of former salt tycoon of Heijing Old Town. The mansion was built during 21 years in mid 19th century and is formed in the shape of the Chinese character wang (王), which means king. It has 108 rooms, which have been left more or less unchanged. Today it serves as an (expensive) hotel for Heijing visitors.
The Ancient Salt Workshop was Heijing’s core place and fortune fountain. The remaining huge water wheels and stages for making salt testify the great prosperity of the bygone times. The salt produced in Heijing is as white as snow. It was and is used for preserving Yunnan’s well-known Xuanwei Ham.” (Christy Huang, 2015)
The third ingredient in the production of Yunnan Xuanwei Ham is the pigs. Traditionally, the rear legs of the Wujin pig breed are used. The breed is known for its high-fat content, muscle quality and thin skin (chinadaily.com).
The breed is usually kept outdoors and is typical in the Xuanwei region. They are normally fed on corn flour, soybean, horse bean, potato, carrot, and buckwheat. They are slow growers, but their meat is of superb quality.
Li Yingqing and Guo Anfei (China Daily) wrote a great article about these pigs for the Yunnan China Daily entitled “Yunnan’s little black pig by the Angry River.”
They write that “there is a quiet little revolution taking place by the banks of Nujiang River, the “angry river”, the upper stretch of the famous Mekong as it passes the narrow gorges near Lijiang. Here, little black pigs wander freely by steep meadows, grazing on wild herbs and foraging as freely as wild animals. They are relatively small, compared to their bigger cousins bred in farms. These sturdy little animals are reared for about two to three years before they are slaughtered and made into the region’s organic hams – called black hams for their deep-colored crusts.” (Yingqing and Anfei)
Li Yingqing and Guo Anfei report on “Wang Yingwen, a 47-year-old farmer who has raised the black pigs for more than 30 years, says the pigs are fed spring water and they live on wild fruits, mushrooms and ants on mountains, an all-organic diet if there was one. (Yingqing and Anfei)
With increased industrialisation came the demand for a faster growing animal. Wujin pigs were being crossed with Duroc (USA), Landrace (Denmark), and York (UK) to achieve faster growth. Wujin x Duroc were crossbred. Other crossbreeds are York x (Wujin x Duroc) and DLY (Duroc x (Landrace x York). Yang and Lu (1987) found that the cross itself does not materially influence the quality of the ham as long as the breed contains 25% Wujin blood. (Kristbergsson and Oliveira, 2016)
In Xuanwei City, pig production is big business! In 2004, the city loaned 120 million yuan to breeders. By this date, the city had 31 breeding facilities each yielding 3000 pigs annually. There were an additional 9600 small breeding facilities. 356 Animal hospitals support the breeding and husbandry operations. In Xuanwei City, 1.2 million pigs were sold in that year. (Kristbergsson and Oliveira, 2016)
Consumers want a great product (consistency, despite volumes offered by industrialised processes) and a great story (focussing on the ancient history of the process and ham itself). Work to accomplish this was funded by the Yunnan Scientific Department, the Yunnan Education Department and Xuanwei City Local Government who all promoted the continued development of the Yunnan Xuanwei Ham (宣威火腿/xuān wēi huó tuǐ). (Kristbergsson and Oliveira, 2016) Modern processing methods moved away from seasonal production and embraced modern processing technology, but the great legends of the past remain as well as tailor-made production techniques catering for year-round production.
Processing Yunnan Xuanwei Ham
The Xuanwei climate explains the production methods used, as is the case with all the great hams around the world. Xuanwei City is located on a low-latitude plateau mansoon climatic area where the north sub-torrid zone, the southern temperature zone, and the mid-temperature zone coexist. Winter lasts from November to January and spring occurs from February to April. February, March, April is sunny and clear and this leads to a low relative humidity during these months. From March to September it is overcast and rainy, and the relative humidity is comparatively high. Winter is the best time to salt the hams according to the old methods to limit microactivity till salt dehydrates the meat and reduces the water activity. The rainy season is best for fermenting the ham. (Kristbergsson and Oliveira, 2016)
As in all meat processing, making the hams start with good meat selection. The process starts in the winter. The animal is killed and all the blood pressed out by hand. Animals are between 90 and 130 kg (live weight) when slaughtered.
A simple flow chart is given by Kristbergsson and Oliveira (2016).
Slaughtering and Trimming
Traditionally Xuanwei people kill the pigs usually before the last frost. They add boiling water to a wok and scrape the pig’s hair. Some people refer to killing the pig as washing the pig. For villagers, the killing of the pig is a sacred ceremony. (China on the Way)
The hind leg is trimmed into an oval shape in the form of a Chinese musical instrument, the pipa. The legs of small pigs are cut in the form of a leaf. The legs cut off along the last lumbar vertebra. After the blood is pressed out, the meat is held for ripening in a cold room at a temperature of 4 to 8 deg C, relative humidity of 75% for 24 hours. Ripened legs are known as green hams. (Kristbergsson and Oliveira, 2016) This step is an enigma to me since I am not sure what is accomplished in such a short period of time. My guess is that it is not technically ripening, but rather allowing any excess fluids to drain out. I will keep interrogating the processing steps to ensure that my sources have the right information.
The green hams are then salted. The salt is a mixture of table salt (25g/kg of leg) and sodium nitrite (0.1g/kg leg). (Kristbergsson and Oliveira, 2016) The inclusion of sodium nitrite is without question a modern development since nitrite curing of meat only became popular after World War I. My instinct tells me that they originally only used salt and later, possibly, sodium nitrate, the production of which has been done for very long in Chinese history.
The salt is rubbed into the hams by hand massaging for around 5 minutes. “The salted hams are then stacked in pallets and held in a cold room at 4 to 8 deg C, 75 to 85% relative humidity for 2 days. Salting procedure is then repeated.” The salt ratios are this time changed to table salt of 30g/kg ham and sodium nitrite is kept at 0.1g/kg leg. The meat is rested for a further 3 days in the chiller after which another salting is done. The ratio of this salting is 15g of table salt per kg of ham and again, sodium nitrite is kept at 0.1g per kg ham. (Kristbergsson and Oliveira, 2016)
According to Li Yingqing and Guo Anfei, “traditionally made hams are cured with half the salt used in factories. Instead, they are allowed to dry-cure for at least eight months to about three years, so the meat has time to mellow and mature.” “The longer the ham is cured, the better the quality and the most popular product now is the three-year-old cured ham.”
The hams are then hung in the drying room with a temperature of 10 to 15 deg C and relative humidity of between 50 and 60%. (Kristbergsson and Oliveira, 2016) Note how the temperature is increased and the relative humidity decreases to facilitate drying from the inside, out.
The excess salt is brushed away and the hams are dried for 40 days. Windows are kept open to facilitate air movement to air drying. Screens are placed in front of openings to prevent flies, other insects and birds from entering. If drying is too fast, a crust will form on the outside of the ham and if it is done too quick, the inside will not be dried and will spoil. If drying is done too long, the meat will be too dry to accommodate the lactic acid bacteria which will be involved in the fermentation process.
Li Yingqing and Guo Anfei reports on the traditional way that drying was done. “If you visit the villages by Nujiang, you may chance upon a strange sight in winter, when the hams are hoisted high on trees so they can catch the best of the drying winds. These trees with hocks of ham hanging from them seem to bear strange fruit indeed.”
After drying, the temperature is raised to 25 deg C. Relative humidity is pushed up to 70% and ideal conditions are created for fermentation. This process lasts for 180 days. Apart from creating an ideal condition for microbes, raising the temperature and humidity favours enzymatic activity, which is important in flavour development due to the partial decomposition of lipids (fat) and proteins. (Kristbergsson and Oliveira, 2016)
“Xuanwei ham is like good wine: the older the better. A ham that’s been aged at least 3 years can be eaten raw like prosciutto di parma.”
Control of Pests
During the curing and drying stages, flies pose a major risk. During fermentation and storage ham moths and mites (eg. tyrophagus putrescentiae) are the major danger. Relative humidity of over 80% attracts flies such as Piophila casei, Dermestes carnivorus beetle and mites. “There has been considerable work done in controlling mite infestation. Microorganisms such as the Streptomyces strain s-368 help prevent and treat mite investigation.” (Kristbergsson and Oliveira, 2016)
Xuanwei hams are evaluated by sensory evaluation. The odor is absorbed by a bamboo stick, used for the evaluation. This is the most traditional absorption method to classify different ham grades. For a detailed discussion and evaluation of this method, see Xia, et. al (2017), Categorization of Chinese Dry-Cured Ham Based on Three Sticks Method by Multiple Sensory Techniques
Storage is done under ambient conditions and the hams can be stored between 2 and 3 years.
“The physical and chemical properties of dry-cured ham are important determinants of its quality (Jiang et al. 1990 ; Careri et al. 1993 ). The lean portion of Xuanwei ham contains 30.4 % protein, 10.9 % fat, 10.3 % amino acids, 42.2 % moisture, and 8.8 % salt (Jiang et al. 1990 ). The whole ham contains 17.6 % protein, 29.1 % fat, 5.6 % amino acids, 24.8 % moisture, and 3.3 % salt (Jiang et al. 1990 ). Many essential elements are present in the ham as are some vitamins. The ham is particularly rich in vitamin E (45 mg/100 g). The characteristic bright red color of Xuanwei ham is mainly attributed to oxymyoglobin and myoglobin. The flavor and taste are associated with the presence of various amino acids and volatile organic compounds . The volatile substances present in Xuanwei ham have been extensively studied (Qiao and Ma 2004 ; Yao et al. 2004 ). Seventy-five compounds were tentatively identified in the volatile fraction. The compounds identified included hydrocarbons, alcohols, aldehydes, ketones, organic acids, esters, and other unspecified compounds.” (Kristbergsson and Oliveira, 2016)
The dominant microorganism on the surface of dry cured hams is mold, which affects quality. During the ripening stage, molds play an important and positive role in flavour and appearance. A study of Iberian dry-cured hams showed that yeasts are predominant during the end of the maturing phase of production whereas Staphylococcus and Micrococcus are absent. This surface yeast population has been shown to be useful for estimating the progress of maturation. Its contribution to curing is suggested to be their proteolytic or lipolytic activity. (Kristbergsson and Oliveira, 2016)
In Xuanwei hams, researchers have shown Streptomyces bacteria to dominate and account for almost half of the Actinomycetes. Aspergilli and Penicillia are common on the surface of Xuanwei hams during June to August. They found 8 species of Aspergillus. A. fumigatus was found to be dominant and accounts for one third of Aspergilli. Generally speaking, a high relative humidity encourages mold development on the surface of the hams. (Kristbergsson and Oliveira, 2016)
The dominant fungi found on Xuanwei hams is yeast. Yeast can be 50% of the total microorganisms found on mature dry-cured hams. Proteolytic and lipolytic activity of yeast is desirable. Towards the end of maturation, yeast dominates on dry-cured hams. (Kristbergsson and Oliveira, 2016)
Which species to be found during the different stages of production depends on temperature and relative humidity. In the Xuanwei region, humidity and temperature are highest during the rainy season. Molds occur almost exclusively on the surface of the hams. Aspergilli and Penicillia occur mostly during May when relative humidity and temperature are high. These fungi peak in July and August. Molds begin to grow in May and are well established by June. Spores are formed in August and September. The quantity of spores falls off gradually in September. (Kristbergsson and Oliveira, 2016)
“The growth of bacteria and Actinomycetes does not seem to be dependent on humidity in the curing room. Levels of bacteria are generally lower than levels of yeast. According to Wang, et al. (2006) yeast on ham multiplies exponentially from the beginning of the salting stage to reach a peak in April, and then the numbers drop and stabilise to around 2 x 107 cfu/g.Yeast levels within the ham show similar variation as the surface yeast. According to Wang et al. (2006) yeast accounts for 60 to 70% of the total microbial population on the surface of the ham. In some cases, no molds have been found growing on the surface of good-quality ham; therefore, some researchers believe that molds do not play a direct role in determining the quality of dry-cured ham, but an opposing view also prevails.” (Kristbergsson and Oliveira, 2016)
“According to the traditional view, high quality Xuanwei ham must have “green growth” (i.e. molds) on it. However, fungi such as Penicillia , Fusarium , and Aspergilli are known to produce mycotoxin in foods such as dry-cured Iberian ham (Núñez et al. 1996 ; Cvetnić and Pepeljnjak 1997 ; Brera et al. 1998 ; Erdogan et al. 2003 ). More than 15 % of the mold strains examined were found to produce mycotoxins in Xuanwei ham (Wang et al. 2006 ). The toxins penetrated to a depth of 0.6 cm in the ham muscle. Because most of the fungi that occur on ham have not been examined for producing mycotoxins , contamination with toxins might be more prevalent than is realized.” (Kristbergsson and Oliveira, 2016)
“The ham must be flame burned and washed before eating, in order to remove the rancid taste.” (China on the Way.)
There are an infinite variety of ways to serve the ham. It can be steamed, boiled, fried, or used as accessories. Old legs can be eaten raw. When cooking, cook either the whole ham or large cuts on a slow fire or slow boil it to retain the flavour.
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chinadaily.com Updated: June 26, 2019
China on the Way, XuanWei Ham
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